Method of making armature coils



March 17, 1931.

v. G. APPLE METHOD OF MAKING" ARMATURE COILS Original Filed Nov. 23, 1927 lNVE/VTOR.

Patented Mar. 17, 1931 UNITE VINCENT Gr. APPLE, OF DAYTON, OHIO METHOD OF MAKING ARFIA'IUEE OOILS Original application filed November 23, 1927, Serial No. 235,282. Patent No. 1,742,190, dated January 7,

1930. Divided and this application This invention is shown, tho not claimed, in my co-pending application Serial Number 235,282 of which this application is a division and relates to single turn bar wound armatures and is particularly applicable where endwise entry of the winding into the core apertures is desired.

The object of the invention is to compose winding loops having both legs of substantially the same cross sectional area but of different cross sectional shape, from bar stock or wire of uniform cross sectional area thruout.

I attain thisobject by the method hereinafter described, reference being had to the drawings wherein Fig. 1 shows a length of wire bent back upon itself to hairpin form.

Fig. 2 shows a hairpin Fig. 1 after one of the legs has been flattened to a wedge shape.

Fig. 3 is a cross section taken at 33 Fig. 2.

Fig. 4 shows how the legs of the hairpin Fig. 2 may be spaced apart to form a loop.

Fig. 5 shows a portion of an end view of a core having apertures adapted to be wound with loops Fig. 4.

Fig. 6 shows a core wherein a complete set of loops Fig. d have been endwise entered, the open ends of the loops projecting beyond.

As is generally known closed or semi-closed winding apertures in armature cores have many advantages. One advantage is greater magnetization for a given number of winding turns due to the distribution of the armature flux over a greater portion of the air gap thru the resulting widened ends of the core teeth at the outer diameter of the armature. Another is the effective manner in which the conductor bars are held against centrifugal force at high rotative speeds. V

A wedge shaped semi-closed winding aperture produces core teeth having widened outer ends. I therefore provide a core having wedge shaped winding apertures, and winding loops having one conductor bar of a cross section which substantially conforms to the wider outer half of an aperture and another conductor bar which substantially con- 59 forms to the narrower inner half of the wind- November 21, 1328. Serial no. $20,901.

ing aperture, so that the two bars when placed one radially above the other will substantially fill the aperture.

The prior art discloses loops conforming to the foregoing specifications so that claim is not herein made to such a loop per se, but rather to the novel, economical and effective method of producing it.

- Fig. 1 shows one step in the method of making a loop of my winding and consists of cutting a length of round wire of standard gauge and folding it back upon itself as at 18 to hairpin form, thus providing two round conductor bars 20 and 21 parallel to each other.

Fig. 2 shows another step employed in producing my loop and consists of bringing one of the two like bars to a different cross section from the other. This may be done by striking in a die comprising-two appropriately inclined planes, by passing the hairpin between suitable rollers, or by any other suit able means which will flatten one bar and leave the other round, or which will flatten one bar but slightly and the other considerably to form a composite wedge. In the embodiment shown bar 20 only is flattened as will appear in Fig. 3 which is a cross section taken at 33 Fig. 2.

Fig. lshows how bars 20 and 2l'ma-y be spread to form a winding loop in which bar 20 is joined to bar 21 at 18 by diagonal back lead portions 22 and 23, bar 20 being adapted to occupy the innerhalf of a core aperture, forming a half turn of the inner layer of the winding, and bar 21 being adapted to occupy the outer half of a core aperture, forming a half turn of the outer layer of the winding. V i

Fig. 5 is a partial endview of a core 24 having the conventional wedge shaped apertures 25, 25, rounded at the top 26 and bottom 27 leaving teeth 28, 28 having parallel sides and widened ends 29, 29 separated by slots 30. The apertures 25 are preferably lined or the legs 20 and 21 coated with insulating material. In the instant case, sheet insulation is bent as at 31 or as at 32 and inserted in the core apertures leaving insulated openings 33 adapted to receive bars 20 and insulated openings 3 L adapted to receive bars 21.

While the method of procedure hereinbefore illustrated contemplates using round bars or wire in the conventional wedge shaped winding apertures, it is obvious that the use of bars or wire of somewhat modified form in C0 'respondingly modified apertures will come within the scope of the invention, and while I have described succeeding steps by which my winding loop may be produced, these steps need not be taken in the sequence named, but may be taken in a different or(; or, and they may be taken singly as indicated, or several, or all may be combined into a single operation, and while winding loops of the character shown are particularl applicable to cores having closed or semi-closed winding apertures thru which they nray be endwise entered they may be used to advantage in cores having open winding slots.

hen loops Fig. 4t are to be used in a core Fig. 5 the bars 20 and 21 must be endwise entered thru the core apertures and this is most conveniently done by the process shown in my Patent Number 1,555,931, where an entire winding is first assembled in cylindrical formation then endwise entered into the core until the open ends of the loops extend thru and beyond the core as shown in Fig. 6.

Having described my invention, 1 claim 1. The method of making a winding loop for a bar wound armature having wedge shaped winding apertures, said loop having one leg adapted to the outer wider half of one of said apertures and the other leg adapted to the inner narrower half of one of said apertures, which consists of selecting wire of a cross section which. substantially conforms to the outer wider half of one of said apertures, cutting a suitable length of said wire, bending it to compose a loop having two parallel legs, and forging said loop to alter the cross sectional contour of one of said legs to conform to the cross section of the inner narrower half of one of said winding apertures.

2. The method of making a winding loop the two legs of which form a composite wedge, which consists of cutting a length of wire of uniform cross section throughout its length, bending it back upon itself to form two parallel legs, and pressing said legs between two appropriately inclined planes substantially as described.

In testimony whereof I hereunto set my hand.

VINCENT G. APPLE. 

